Jason is... intimately familiar with death. It's part of the job; the risk they all take in this whole vigilante business. He's accepted that, just like most of the family has - look this is why Bruce keeps a goddamn Lazarus Pit in the basement, right? Because no matter how careful everyone might be, no matter how well they fight or how strong they are - someone could always die.
And look, he doesn't mean to be blasé about it. Death sucks, he knows that better than most people. It's just, y'know... part of the deal. He'd call it a stretch to say he's 'used to it' - but at the same time, he's got a routine for it, y'know? Drag the person to the Pit; help 'em climb back out of it; hand 'em off to Alfred for, like, proper emotional care; and then Red Hood's gonna go beat the crap outta whoever killed 'em. Vengeance and catharsis in one package. Healthy? Probably not. But hey, it helps.
Except... this time? There's no one to smack around. There's no one to blame. No one to be mad at. This time, nobody killed his sibling. This time he had to watch his baby sibling slowly waste away in a hospital bed, struck with an illness even the vast Wayne fortune hadn't been able to fund a cure for fast enough.
And yeah, the Pit still works. Not the same way, exactly. It can bring you back, alive and free of the illness that took you, but it can't put the weight back on your body. Can't return you to peak strength. It heals the thing that killed you - not all the side effects. It's gonna take more than a plate of cookies and a 'Congratz on your first resurrection' club T-shirt to get you back to feeling okay again.
And Jason's not sure what to do with himself. This isn't how it goes. This isn't how he's used to losing people. He's got nobody to be pissed at for this except the vague concept of illness and mortality, and it's bugging him.
Which, y'know, means he can only imagine how you must be feeling. "Hey, kid." He plops down next to you on the couch with a huff. "You doin' okay?"